In the field of food or beverage preparation by mixing a precursor ingredient contained in a container, with a mixing ingredient fed from an pressurized source contained in a food or beverage preparation machine.
In the following description, it will be considered that the source of mixing ingredient is a pressurized water source. Such a limitation should not be taken as a limitation of the invention scope. The container described and claimed therein can be used with other sources of mixing ingredient.
Also, in the rest of the present description, and for simplification purposes, it will be considered that the container of the invention is a beverage container, for instance a beverage capsule. Again, this should not be taken as a strict limitation of the scope of the invention. The container of the invention can be of another type than a capsule, for instance it can be a soft pad, a pod, a sachet, a rigid or semi-rigid cartridge, or a combination thereof. It can be made of any type of material like plastic, paper, cardboard, metal or alloy, glass, synthetic or natural rubber or elastomer, or a combination thereof. Preferably, materials will be chosen from cost-effective and ecologic material, having barrier properties, at least against moisture and oxygen. The precursor ingredient contained in the container of the invention can be of any type for preparing a food or a beverage product. In the following a beverage container will be described in more detail. However, the principle of the invention can be applied to any container for preparation of an edible preparation, be it a beverage or a semi-solid or solid food, such as for example but not limited to: ice cream, potage, smoothies, cooking dough, soup comprising solid elements such as croutons, or even fully solid food such as pastry.
Generally, food or beverage preparation machines are well known in the food science and consumer goods area. Such machines allow a consumer to prepare at home a given type of food or beverage, for instance a coffee-based beverage, e.g. an espresso or a brew-like coffee cup, or other types of beverages like chocolate, teas, soups and the like.
Today, most beverage preparation machines for in-home beverage preparation comprise a system made of a machine which can accommodate portioned ingredients for the preparation of the beverage. Such portions can be soft pods or pads, or sachets, but more and more systems use semi-rigid or rigid portions such as rigid pods or capsules.
The machine comprises a receptacle or cavity for accommodating said capsule and a fluid injection system for injecting a fluid, preferably water, under pressure into the capsule. Water injected under pressure in the capsule, for the preparation of a coffee beverage according to the present invention, is preferably hot, that is to say at a temperature above 70° C. However, in some particular instances, it might also be at ambient temperature, or even chilled. The pressure (relative to atmospheric pressure) inside the container/capsule chamber during extraction and/or dissolution of the capsule contents, until the capsule opens, increases up to typically about 1 to about 8 bar for dissolution products and about 2 to about 12 bar for extraction of roast and ground coffee. Such a preparation process differs a lot from the so-called “brewing” process of beverage preparation—particularly for tea and coffee, in that brewing involves a long time of infusion of the ingredient by a fluid (e.g. hot water), whereas the beverage preparation process allows a consumer to prepare a beverage, for instance coffee, within a few seconds.
The principle of extracting and/or dissolving the contents of a closed capsule under pressure is known, and consists typically of inserting the capsule in a receptacle or cavity of a machine, injecting a quantity of pressurized water into the capsule, generally after piercing a face of the capsule with a piercing injection element such as a fluid injection needle mounted on the machine, so as to create a pressurized environment inside the capsule either to extract the substance or dissolve it, and then release the extracted substance or the dissolved substance through the capsule. Capsules allowing the application of this principle have already been described for example in applicant's European patents no. EP 1472156 B1, and EP 1784344 B1.
Machines allowing the application of this principle have already been described for example in patents CH 605 293 and EP 242 556. According to these documents, the machine comprises a receptacle or cavity for the capsule and a perforation and injection element made in the form of a hollow needle comprising in its distal region one or more liquid injection orifices. The needle has a dual function in that it opens the top portion of the capsule on the one hand, and that it forms the water inlet channel into the capsule on the other hand.
The machine further comprises a fluid tank—in most cases this fluid is water—for storing the fluid that is used to dissolve and/or infuse and/or extract under pressure the ingredient(s) contained in the capsule. The machine comprises a heating element such as a boiler or a heat exchanger, which is able to warm up the water used therein to working temperatures (classically temperatures up to 80-90° C.). Finally, the machine comprises a pump element for circulating the water from the tank to the capsule, optionally though the heating element. The way the water circulates within the machine is e.g. selected via a selecting valve means, such as for instance a peristaltic valve of the type described in applicant's European patent EP 2162653 B1.
When the beverage to be prepared is coffee, one interesting way to prepare the coffee is to provide the consumer with a capsule containing roast and ground coffee powder, which is to be extracted with hot water injected therein.
In many instances, the machine comprises a capsule holder for holding a capsule, which is intended to be inserted in and removed from a corresponding cavity or receptacle of the machine. When a capsule holder is loaded with a capsule and inserted within the machine in a functional manner, the water injection means of the machine can fluidly connect to the capsule to inject water therein for a food preparation, as described above. A capsule holder was described for example in applicant's European patent EP 1967100 B1.
In most known food or beverage containers (e.g. capsules) are designed to function with food and beverage preparation machines, that comprise means for injecting a mixing ingredient (e.g. water) inside the capsule which are movable, more precisely, that are displaced towards the container when said container is inserted inside said machine in functional configuration. Typically, such injection means of the machine are displaced after the container (e.g. the capsule) is inserted therein and the machine is closed. In such a configuration, the injection means of the machine protrude in the compartment used for loading the capsule. Although such a fluid connection principle works and is commonly used, it poses a certain number of issues, among which ensuring a proper and reliable leaktightness at the interface between the capsule and the machine. The reason is that capsules are usually manufactured with thin walls (for ecological and cost reasons), so that they can easily be deformed when an external pressure is exerted thereon. At the time the injection means of the machine are moved towards the capsule, the latter tends to deform, even slightly, which creates leaking channels. Such leaking risks require additional technical design and reinforcement of the capsules and machines to guarantee leaktightness, which are expensive and complex to put in place.
Furthermore, capsules have been developed for such an application of food preparation, and in particular for beverage preparation, which are described and claimed in applicant's European patent EP 1784344 B1, or in European patent application EP 2062831.
In short, such capsules comprise typically:                a hollow body and an injection wall which is impermeable to liquids and to air and which is attached to the body and adapted to be punctured by e.g. an injection needle of the machine,        a chamber containing a bed of roast and ground coffee to be extracted, or a soluble ingredient or mix of soluble ingredients,        an aluminium membrane disposed at the bottom end of the capsule, closing the capsule, for retaining the internal pressure in the chamber.        
The aluminium membrane is designed for being pierced with piercing means that are either integral with the capsule, or located outside of said capsule, for example within a capsule holder of the machine.
The piercing means are adapted for piercing dispensing holes in the aluminium membrane when the internal pressure inside the chamber reaches a certain pre-determined value.
Also, optionally, the capsule can further comprise means configured to break the jet of fluid so as to reduce the speed of the jet of fluid injected into the capsule and distribute the fluid across the bed of substance at a reduced speed.
In many food and beverage preparation systems, several types of containers (such as capsules) can be used with the same machine. Some capsules can be used for infusion of a stationery precursor ingredient (e.g. roast and ground coffee) through which the mixing ingredient (e.g. hot water) flows. Some other capsules may also contain a soluble precursor ingredient, such as a soluble milk or chocolate powder, which is dissolved by mixing with a mixing ingredient like hot water.
Particularly in case the precursor ingredient contained in the capsule is soluble, it requires a large headspace built-in the capsule to ensure that the mixing ingredient (which is preferably liquid) injected from the machine within the capsule, can properly mix with the precursor ingredient contained in said capsule. Such a proper mixing is guaranteed by a whirling movement of the ingredients inside the capsule. The whirling movement requires sufficient space within the capsule.
In known solutions, there is a need to enlarge the volume of the capsule way beyond the volume strictly required for containing the precursor ingredient, in order to provide sufficient headspace for the mixing process to take effect. However, bigger capsules require additional packaging material to make the capsule. This is undesirable for convenience, cost and ecological reasons. Headspace inside the capsule is therefore considered wasted volume, and should be avoided as much as possible.
It is therefore an objective of the present invention to provide a container which obviates the drawbacks of the known food and beverage containers and systems.